Hemming machine or fixture



J. A. KOLLAR; EFAL 3 L HEMMING MACHINE 0R FIXIUREZ June 29, 1965 a: Sheets-Sheen. 1

Filed Feb. 2'7, 1963 INVENTORS 03901:: A. KOAAR A rroR/w'rs June 29, 1965 J, A. KOLLAR ETAL 3,191,414

HEMMING MACHINE OR FIXTURE Filed Feb. 27, 1963 5 Sheets-Sheet 2- 5 i L w J a /d 7 w A 4 l n/7/////// 5 a United States Patent 3,191,414 HEMMING MACHINE OR FIX James A. Kollar, 6544 Knollwood Circle, and Anthony J. llqartilne, 25425 Tweed Drive, both of Birmingham,

Filed Feb. 27, 1963, Ser. No. 261, 438 12 Claims. (Cl. 72-48) This invention relates to a single machine mechanism for developing tool movement in two different directions in sequential stages or in a combined stage. The mechanism first moves the tool or die in a side direction to fold an upstanding flange on a sheet metal part. Then the mechanism moves the tool in a down direction to clinch the folded flange against the part in a compressed hem. The novel hemming machine thus hems the part in a single production operation.

Hemming the edge of sheet metal parts is desirable in certain manufacturing operations. The fabrication of an automobile body door provides an illustrative example. Here it is advantageous to fold over a flange at the edge of the door panel and then compress it upon the part in a hem to provide a smooth strong edge. A re-enforcing panel may be placed in the door panel and the hem may envelope the edge of the re-enforcing panel securing them together.

The door panel and re-enforcing panel used as an example have complex contours and are intricately outlined so that the hem traverses many complex curves, radii, indentations, and protrusions together with transversely contoured hills and valleys. Thus, folding the upstanding flange on a partially fabricated door panel over the reenforcing panel involves expanding or stretching the hem flange material in some locations and involves gathering and compressing the material of the hem flange in other locations.

The usual practice in industry has been to use two separate hemming machines to make a hem on a part that already has an upstanding flange set-up in forming the part. The first hemming machine bends the upstanding flange over the part with a side tool motion relatively substantially parallel to the part and transverse to the flange in its upstanding position. After this first hemming operation, the flange lies bent over the part but in an unclinched condition. This first tool motion or operation cannot clinch the hem.

In the past practice usual in industry, the second hemming machine drives the now folded flange against part in a clinched hem with a down motion relatively transverse to both the flange and the part. After the second machine operation, the hem is clinched against the part. Thus, two machines have been required in usual industrial practice necessitating two production operations and transferring the part between the machines. 1

The various machines, fixtures, and devices which have been employed in the prior art to produce a hemon complex sheet metal articles have not proven entirely satisfactory inasmuch as they are large and cumbersome, complicated in design and construction, expensive to manufacture, difiicult to use, costly and slow in operation. Moreover the prior art devices have been engineered to a particular job so that they are not useable from model to model and are usually scrapped in their entirety.

With the foregoing in view, the primary object of the invention is to provide a machine, device, or fixture for hemming sheet metal articles which is compact and facile, simple in design and construction, inexpensive to manufacture, easy to use, inexpensive and rapid in operation, and which produces a highly satisfactory hem on complex sheet metal articles in a single operation.

An object of the invention is to provide individual hemming units and which are fixed around a hemming machine at desired locations and in various angular positions.

An object of the invention is to provide hemming unit fixtures which can be used on successive automobile models year after year by taking the units off the old model machine set-up and using them on the new model machine set-up.

An object of the invention is to provide hemming fixtures which can be built and stocked as standard items.

An object of the invention is to provide actuating means for effecting tool or die movement in a single operation first in a side direction relative to an upstanding flange on a sheet metal part to fold the flange over on the body of the part in a partially formed hem and second in a down direction transverse to the movement in the side di rection to clinch the folded flange in a smooth solidly compacted hem.

An object of the invention is to provide a machine having actuating units stationed at various positions around a part such as door panel to hem the entire panel in one operation.

An object of the invention is to provide compact actuating units which project a minimum distance on the machine thereby saving floor space and permitting maximum access to the machine.

An object of the invention is to provide machine base structure for operating a contoured hemming steel which first moves in a side direction to fold the flange on the part and second then moves in a down direction trans verse to both the part and the folded flange to clinch the flange on the part in a compacted hem.

An object of the invention is to provide actuating means for moving the hemming steel in a downwardly clinching direction which prior to its operation provides a pivotal axis for the device during the movement in a side direction to fold the flange.

An object of the invention is to provide actuating means for moving the device in a side direction to fold the flange which is capable after its own function of then allowing the transverse downwardly directed movement to clinch the flange in a solid hem.

An object of the invention is to provide a one operation mechanism having two stages of transverse movement wherein the stages are selectively operable sequentially or in combination as desired.

These and other objects of the invention will become apparent by reference to the following description of a hemming machine, device, or fixture embodying the invention taken in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of the device seen in FIG. 2 showing the rear, top, and one end of a hemming machine unit embodying the invention.

FIG. 2 is a rear elevational view of the device seen in FIG. 1.

FIG. 3 is an enlarged cross sectional view of FIG. 2 taken on the line 33 thereof showing the device in the retracted position and additionally showing a workpiece such as a sheet metal part having an upstanding flange.

FIG. 4 is a view similar to FIG. 3 showing the device after sideward folding movement has occurred with the workpiece flange in folded condition.

FIG. 5 is a slightly enlarged partial cross sectional view of the workpiece location of the device of FIGS. 3 and 4 showing initial contact with the flange in solid lines and the sidewardly advanced folding positions in dotted lines as the device moves from the position of FIG. 3 to the position of FIG. 4.

FIG. 6 is a view similar to FIG. 5 showing the folded position of the workpiece flange after the movement in a side direction.

FIG. 7 is a view similar to FIGS. 3 and 4 showing the device after movement in a downward direction has occurred to clinch the flange in a hem; and

FIG. 8 is a slightly enlarged partial view of FIG. 7 similar to FIGS. 5 and 6 showing the clinched hem and the machine parts in more detail.

Referring now to the drawings. wherein like numerals refer to like and corresponding parts throughout the several views, the hemming machine unit disclosed therein to illustrate the invention comprises stationary portions rela tive to which folding movement in a side direction occurs and relative to which clinching movement in a down direction occurs. A drag-link jaw 20 is the principal moving part and is shown and described herein paired with a like jaw 20. One or more jaws may be used in a unit as desired. Each jaw 20 has upper and lower ends.

The paired jaws 20 are pivotally mounted at their lower ends providing a bottom pivot point. They are swung at their top about the bottom pivot point to effect folding movement in 'a side direction relative to a workpiece flange. This folds the flange over. The jaws 20 are then moved in a downward direction to clinch the folded flange in a compact hem.

The hemming machine unit is mounted on a base structure 21 which may be a machine frame or table. 22 on the base structure 21 limits side movement of the jaws 21. The base structure 21 has an anvil such as a contoured steel form 23 and a depressable workpiece positioning plunger 24 which locates a workpiece 25.

The stationary portions of the hemming unit comprise paired brackets 26 which are bolted, doweled, and heeled to the base structure 21. A bottom pivot pin 27 and an intermediate pivot pin 28 are supported on the brackets 26. Paired bearing blocks 31 at the top of the brackets 26 support a pair of trunnions 29 on a cylinder block 30. The pin 27, the pin 28, and the trunnions'29 constitute fixed pivot points as they are supported on the brackets 26 which are anchored on the base structure 21.

A cross support bar 32 is fixed on the brackets 26. Side slide bearings 36 are carried by jaws 20. The bearings 36 on the jaws Ztlslidably bear against the ends of the bar 32. This supports the jaws 20 against transverse thrust.

Referring now to the movable components of the hemming unit, paired rocker arms 40 are pivotally mounted at their inner ends on the bottom pivot pin 27. At their outer ends the rocker arms 40 are equipped with hearing blocks 41 pivotally supporting a pair of trunnions 42 on a cylinder block 43. A bottom hydraulic cylinder 44 is mounted on the cylinder block 43. This cylinder powers down movement of the jaws 21. The cylinder 44 has a piston rod 45 actuating a head 46 through which a toggle knee joint pivot pin 47 is disposed.

A pair of upper toggle links 50 are pivoted on the knee pin 47 at their lower ends. The upper toggle links 50 are pivotally hung on the fixed middle pivot pin 28 at their upper ends. A pair of lower toggle links 59 are pivoted on the knee pin 47 at their upper ends and are pivotally connected to the rocker arms 40 by a lower cross-connected rod 52.

The outer ends of the rocker arms 40 are thus hung on the brackets 26 by the toggle links 50 and 51. Movement of the toggle links at the knee joint pin 47 moves the outer ends of the rocker arms 26 up and down with the inner end of the rocker arms 40 pivoting on the fixed bottom pin 27.

The cross-connecting rod 52 spanning the rocker arms 40 is also pivotally disposed through the jaws 29. The cross-connecting rod 52, as positioned and held by the rocker arms 40 and associated toggle linkage constitutes the jaw 26) bottom pivot point for swinging the top of the jaw in a side direction against the workpiece flange 35 to fold the flange. Thus, the jaws 20 are pivotally disposed on the cross-connecting rod 52.

The head 46 on the piston rod 45 has an abutment or dog 53 which contacts a stop 54 bolted on'the rocker arms A stop 44 The stop 54 is adjustable relative to the dog 53 via spacer shims 55 which may be inserted or removed as desired. The contact between the stop 54 and dog 53 limit the angular pivoting action of the toggle links 50 and 51 to limit the upward movement of the rocker arms 49 at the desired location to properly position the pivotal axis of the lower cross-connecting rod 52 which controls the relative vertical position of the jaws 20 during their sideward pivotal movement.

Cocking the toggle links 50 and 51 shortens their combined extension from the fixed middle pivot pin 28 to the rod 52. When the links 50 and 51 shorten their extension, they elevate the cross-connecting rod 52. This moves the rocker arms 40 and jaws 20 upwardly. This raises the hemming steel 67 on the jaws 20 relative to the anvil 23 on the base structure 21. Straightening the toggle links 54 and 51 lengthens their combined extension from the fixed middle pivot pin 28 moving the rocker arms 4t? and jaws 2t downwardly. This lowers the hemming steel 67 on the jaws 2t) relative to the anvil 23 on the base structure 21. This action produces the downward clinching motion.

A top hydraulic cylinder 60 is mounted on the cylinder block 30 and has a piston rod 61 connected to a head 62 pivotally connected to the swing jaws 20 at their tops by an upper king pin 63. The cylinder 60 powers the side movement of the jaws 2t). Actuation of the top cylinder 60 advances and retracts the swing jaws 20 in a side pivotal direction relative to the anvil 23 with the jaws pivoting on the lower cross-connecting rod 52. The lower cross-connecting rod 52 is held in a fixed position with the toggle links 50 and 51 cocked as seen in FIGS. 3 and 4. This position is held by the bottom cylinder 44 holding the stops 53 and 54 in abutment.

A cross head 64 interconnects the paired swing jaws 29 at their tops and a cross strut 65 interconnects the swing jaws 20 at their bottoms. The bearing plates 36 on the swing jaws 20 slide relative to the ends of the spacer bar 32 fixed on the brackets 26. The swing jaws 20 have a front slide bearing 38 which abuts the stop 22 on the base structure 21. Contact between the bearing 38 and the stop 22 limits inward swinging slide movement of the jaws 20. Either or both stops may be adjustable as to projection to limit side movement of the swing jaws Ztl to locate the jaws as desired. The slide bearing 38 slides relative to the stop 22 when the jaws 20 are moved downwardly. Other suitable bearings may be positioned between the moving parts such as the pins and rods which constitute the fixed and movable pivot points.

A hemming steel 67 is bolted to the cross head 64 and rides the plungers 24 so as to displace them prior to contact with the workpiece 25 upstanding flange 35. The hemming steel 67 is matingly contoured relative to the anvil 23 so as to insure compaction of the workpiece hem.

Preparatory to the hemming operation, FIG. 3, the bottom down power hydraulic cylinder 44 is actuated to retract the piston rod 45. This pivots the toggle links 50 and 51 knee joint angularly cocking the links and shortening their combined extension from the fixed pivot pin 28 raising the rocker arms 40 and elevating the swing jaws 20. The dog 53 on the head 46 at the knee joint and the stop 54 on the rocker arm 40 limits the upward movement and oppose the force of the bottom cylinder 44. This locks the bottom cross-connecting rod 52 as a stationary pivot point adjacent the bottom of the jaws 20. In their swinging side motion the jaws pivot about this point.

The top side power hydraulic cylinder 60 is actuated to retract the piston rod 61 which licates the tops of the swing jaws 20 and the hemming steel 61 in the outwardly swung retracted position. FIG. 3 illustrates the foregoing condition. The workpiece 25 is'then placed in the position shown in the drawings with the flange 35 behind the plungers 24. At this point the jaws 20 and hemming steel 67 are elevated relative to the anvil 23 by the bottom cylinder 44 withdrawing the piston rod 45. At this point the jaws 20 and hemming steel 67 are swung away from the anvil 23 by the top cylinder 60 withdrawing the piston rod 61. Another member such as the reinforcing panel 98 may be clinched in the hem.

In the first stage of operation, the side power top hydraulic cylinder 60 is actuated to extend the piston rod 61 which swings the swing jaws 20 as pivoted onthe cross-connecting rod 52 in a side direction moving the hemming steel 23 against the workpiece flange 35 as limited by the stop 22 on the base structure 21. The movement just described moves the hemming steel 67 relative to the workpiece flange 35 from the position of FIGS. 3 and 5 through the dotted line position of FIG. 5 to the solid line position of FIGS. 2 and 6. This folds .the flange with movement in a side direction relative to the flange. The extended position of the piston rod 61 is maintained throughout the second stage of operation now described.

In the second stage of operation, down movement bottom hydraulic cylinder 44 is actuated to extend the piston rod 45 which pivots the toggle knee joint from a cocked position to a straightened position extending the toggle links 50 and 51 combined extension against the fixed pivot pin 28 thrusting the lower cross-connecting rod 52 downwardly. This moves the jaws 20 downwardly carrying the hemming steel 67 downward relative to the anvil 23 from the position of FIGS. 4 and 6 to the position of FIGS. 7 and 8. This clinches the flange 35 in a compacted smooth hem. The downward clinching movement of the hemming steel relative to the flange is transverse to the sideward folding movement of the hemming steel relative to the flange previously described. l

The cylinders are then actuated to retract their respective piston rods as previously described. This clears the hemming steel 67 from'a position over the workpiece 25. The now hemmed workpiece 25 is then removed. Another flanged workpiece is inserted and the hemming operation repeated.

The machine unit shown and described illustrates the invention and is not intended to limit the invention. The fixed pivot points at the pins 27 and 28 and the trunnions 29 may be mounted on separate means and the various stops, bearings, and structural members may be shaped, dimensioned, and integrated to suit the workpiece and the hemming operation. The automobile door panel is only illustrative and any sheet metal part may be hemmed by use of the invention.

In high-production manufacture, a plurality of hemming units are located about the base structure and the workpiece is completely hemmed in position on the anvils by the hemming steels of the units. The various hemming steels may be advanced sequentially or at the same time. Adjacent hemming steels may overlap when alternately advanced to insure hem continuity making time staggered operation desirable.

In a high-production, machine servo-mechanisms are used to actuate the device as desired and they are controlled by automatic cycling equipment set in action by a manual start switch. Automatic loading, clamping, and unloading means may be integrated in the automatic cycle to increase the rate of production.

While hydraulic cylinders have been shown as the power means to actuate the hemming unit, it is obvious that screw jacks or other power means may be used. The direction of movement and the locations of parts shown and described arerelative and obviously may be changed, reversed, modified and otherwise disposed.

The hemming machine unit, from the brackets 26 through the actuating mechanism to the jaws 20, is a unitized actuating mechanism which may be used repeatedly by fastening the brackets to a machine frame and fitting the jaws with the proper size cross head 64 and desirably shaped hemming steel 67. Thus, the unit may be used from model to model or may be used to hem various parts of the same model.

In a long hem dimension, a long cross-head 64 and hemming steel 67 may be used and a plurality of units operably connected to the cross head. In short hem dimensions, single units with short cross-heads 64 and hemming steels 67 may be used. Thus, the hemming unit is very adaptable.

The novel hemming unit with the features shown and described constitutes a compact, durable, and facile mechanism easily integrated, controlled, and operated singly and in combination with like units.

Although but a single embodiment of the invention has been disclosed and described in detail, it is obvious that many changes may be made in the size, shape, detail, and arrangement of the various elements of the invention within the scope of the appended claims.

We claim:

1. A hemming machine actuating unit initially developing motion in a side direction to fold an upstanding workpiece fiange over on the workpiece and then developing motion in a down direction to clinch the flange against the workpiece in a smooth ironed-out hem comprising,

a base structureincluding an anvil such as a shaped form for supporting a workpiece in the hem location,

at least one bracket fixed on said base structure; bottom, intermediate, and top pins constituting fixed pivot points supported on said bracket,

toggle links having a first end pivoted on said bracket intermediate pin, a knee joint, and a second end,

at least one rocker arm having an inner end pivoted on said bottom pin, an intermediate portion pivotally connected to said toggle links second end, and an outer end,

clinch power means on said rocker arm outer end connected to said toggle knee joint to pivot said knee joint to cook said links to raise said rocker arm and to straighten said links to lower said rocker arm,

at least one jaw having a bottom end pivotally connected to said rocker arm for raising and lowering therewith; said jaw having an upper end including a hemming steelpositioned relative to said anvil;

and

fold power means on said top pin pivotally connected to said jaw upper end for moving said hemming steel in a side direction relative to said anvil;

said fold power means upon activation moving said jaw and hemming steel in a side direction to fold a flange over on a workpiece on said anvil;

said clinch power means upon activation moving said links, jaw, and hemming steel in a down direction to clinch a flange down on a workpiece on said anvil in an ironed-out hem.

2. Actuating mean-s for a hemming machine initially 'moving in a side direction to fold an upstanding flange 'over on a workpiece and then moving in a down direction to clinch the flange against the workpiece in an ironed out hem comprising,

at least one bracket,

bottom, intermediate, and top pins supported on said bracket constituting fixed pivot points,

at least one rocker arm having an inner end pivoted on said bottom pin,

at least one jaw having .a bottom end pivotally connected to said rocker arm at a point spaced from said'rocker arm inner end; said jaw having an upper end;

fold power means pivotally mounted on said bracket top pin and pivotally connected to said jaw upper end for swinging said jaw in a side direction relative to a workpiece to fold a flange over on a workpiece;

toggle links having an upper end pivotally mounted on said intermediate pin, an intermediate knee joint, and

a bottom end pivotally connected to said rocker arm;

7 said rocker arm having an outer end; and I clinch power means connected to said toggle links knee joint actuating said links to move said rocker arm and jaw in a down direction relative to a workpiece to clinch the'folded flange on the workpiece in an ironed-out hem.

3. A hemming machine initially developing motion in one direction to told an upstanding workpiece flange over on the workpiece and then developing motion in a transverse direction to clinch the flange against the workpiece in a smooth ironed-"out hem comprising,

a base structure including an anvil such as a shaped form for supporting a workpiece in the hem location, support means on said base structure,

bottom, intermediate and top pins constituting fixed pivot points on said support means,

toggle links having a first end pivoted on said intermediate pin, a knee joint, and a second end, paired rocker arms each having an inner end pivoted on said bottom pin, an intermediate portion pivotally connected to said toggle links second end, and an outer end,

clinch power means on said rocker arm outer ends connected to said toggle knee joint to pivot said knee joint to cock said links to raise said rocker arms and to straighten said links to lower said rocker a-rms,

paired jaws each aving a bottom end pivotally connected to said rocker arm for raising and lowering therewith; said jaws each having an upper end including an attached hemming steel positioned relative to said anvil; and

fold power means on said top pin pivotally connected to said jaws upper ends for moving said hemming steel in one direction relative to said anvil;

said fold power means upon activation moving said jaws and hemming steel in a side direction to fold a flange over on a workpiece on said anvil;

said clinch power means upon activation moving said links, jaws, and hemming steel in a transvense down direction to clinch a flange on a workpiece on said anvil in a hem.

'4. Actuating means for a hemming machine initially moving in one direction to told an upstanding flange over on a workpiece and then moving in a transverse direction to clinch the flange against the workpiece in a hem comprising,

support means;

bottom, intermediate, and top pins on said support means constituting fixed pivot points,

paired rocker arms each having an inner end pivoted on said bottom pin,

paired jaws each having a bottom end pivotally connected to said rocker arms at a point spaced from said rocker arms inner ends; said jaw having-an up per end; a fold power means pivotally mounted on said top pin and pivotally connected to said jaws upper ends for swinging said jaws in one direction relative to a workpiece to fold a flange on a workpiece; said rocker arms having an outer end; toggle links having a top end pivotally mounted on said intermediate pin, an intermediate knee joint, and a bottom end pivotally connected to said rocker arms;

said rocker arms each having an outer end; and

clinch power means connected to said toggle link-s knee joint actuating said links to move said rocker arms and jaws in a down direction relative to a workpiece to clinch the folded flange on the workpiece in a hem.

5. Actuating means for moving one machine tool part relative to another machine tool pant comprising,

a base structure, a stationary tool part on said base structure, first pivot means on said base structure, a rocker arm having a first end pivotally connected to said first pivot means,

second pivot means on said base structure,

toggle links having one end pivotally connected to said second pivot means and an opposite end pivotally connected to said rocker arm at a point spaced from said first pivot means, and an intermediate knee joint,

first power developing means connected to said toggle link knee joint for actuating said toggle links to move said rocker arm,

a jaw connected to said rocker arm for movement therewith relative to said stationary tool pant,

a movable tool part on said jaw, and

second power developing means mounted on said base structure and connected to said jaw to move said jaw in a direction transverse to said toggle links;

actuation of said toggle links moving said jaw and said movable tool part in a direction relative to one plane and actuation of said second power developing means moving said jaw and said movable tool part in a dierection relative to a second plane transverse to said one plane;

said movable tool part thereby being movable relative to said stationary tool part in two directions.

6. Actuating means for moving a first movable machine part relative to [a second stationary machine part comprising,

a support, 7

a first fixed pin on said support,

a rocker arm having a first end pivotally connected to said first pin,

a second pin on said support,

toggle links having one end pivotally connected to said second pin and an opposite end pivotally connected to said rocker arm at a point spaced from said first pin, and an intermediate knee joint,

first power developing means mounted on said rocker arm connected to said toggle link joint for actuating said toggle links to move said rocker arm in one plane,

a jaw connected to said rocker arm for movement therewith relative to said support,

said jaw constituting a first movable machine par-t,

second power developing means mounted on said support and connected to said jaw to move said jaw in a second plane,

actuation of said toggle links moving said jaw in a direction relative to said one plane and actuation of said second power developing means moving said jaw in a direction transverse to said one plane.

7. Actuating means for moving a movable machine part relative to a stationary machine part comprising a support constituting a stationary machine part,

a jaw adjacent said support constituting a movable machine part, said jaw having opposite ends;

first power means mounted on said support and connected to one end of a said jaw so integrated to move said jaw in a side direction relative to said support,

toggle links connected between said support and the other end of said jaw so integrated to move said jaw relative to said support in a transverse direction relative to said first power means;

said first power means positioning said jaw at its one end relative to said toggle links;

a rocker arm pivotally connected between said jaw and said base structure positioning said jaw at the other end relative to said toggle links;

said toggle links having a knee joint; and second power means connected to said toggle links knee joint for cocking and straightening said toggle links to move said jaw in a transverse direction relative to said first power means direction of jaw movement.

8. A force developing mechanism comprising a support such as a bracket 2. first pin constituting a first fixed pivot point on said support,

a rocker arm having one end pivoted on said first pin;

said rocker arm having an intermediate portion and an extending end;

a first shaft on said rocker arm intermediate portion constituting a first movable pivot point,

a second pin on said support constituting a second fixed pivot point on said support,

toggle links having inner ends pivoted together in a knee joint and outer extending ends; one said link outer end being pivotally connected to said second fixed pin on said support;

the other said link outer end being pivotally connected to said first movable pivot point shaft on said rocker arm;

pivoting said toggle links at their knee joint from a relative straight line position to a relative angular position shortening their combined extension pivoting said rocker arm on said first fixed point pin toward said second fixed pivot pin;

pivoting said toggle link at their knee joint from a relative angular position toward a relative straight line position lengthening their combinedextension pivoting said rocker arm on said first fixed pivot pin away from said second fixed pivot pin,

and power means mounted on said rocker arm extending end and connected to said toggle knee joint for pivoting said toggle knee joint relative to its pivoted ends;

said power means being pivotally connected to said rocker arm outer end and to said toggle knee joint to permit relative movement therebetween occasioned by the relative movement between said rocker arm outer end and said toggle knee joint.

9. In a device as set forth in claim 8,

stop means on said arm and on said toggle links for limiting toggle knee joint angular movement fixedly locating said rocker arm at a definite secured position such as for providing a fixed reaction point.

10. In a device as set forth in claim 8,

a stop on one said toggle link and a stop on said arm adapted to abut one another at a desired point in their movement relative to one another.

11. In a device as set forth in claim 8,

a jaw pivotally connected to said rocker arm; movement of said rocker arm moving said jaw in a first direction of movement;

and second power means pivotally connected to said support and to said jaw to move said jaw in a direction substantially transverse to the direction of movement effected on said jaw by said rocker arm movement.

12. In a device as set forth in claim 11,

a stop means on said jaw and said frame limiting movement of said jaw by said second power means.

References Cited by the Examiner UNITED STATES PATENTS 1,720,133 7/29 Le Roy 153-12 2,959,205 11/60 Day 153-15 30 CHARLES W. LANHAM, Primary Examiner. 

1. A HEMMING MACHINE ACTUATING UNIT INITIALLY DEVELOPING MOTION IN A SIDE DIRECTION TO FOLD AN UPSTANDING WORKPIECE FLANGE OVER ON THE WORKPIECE AND THEN DEVELOPING MOTION IN A DOWN DIRECTION TO CLINCH THE FLANGE AGAINST THE WORKPIECE IN A SMOOTH IRONED-OUT HEM COMPRISING, A BASE STRUCTURE INCLUDING AN ANVIL SUCH AS A SHAPED FORM FOR SUPPORTING A WORKPIECE IN THE HEM LOCATION, AT LEAST ONE BRACKET ON SAID BASE STRUCTURE; BOTTOM, INTERMEDIATE, AND TOP PINS CONSTITUTING FIXED PIVOT POINTS SUPPORTED ON SAID BRACKET, TOGGLE LINKS HAVING A FIRST END PIVOTED ON SAID BRACKET INTERMEDIATE PIN, A KNEE JOINT AND A SECOND END, AT LEAST ONE ROCKER ARM HAVING AN INNER END PIVOTED ON SAID BOTTOM PIN, AN INTERMEDIATE PORTION PIVOTALLY CONNECTED TO SAID TOGGLE LINKS SECOND END, AND AN OUTER END, CLINCH POWER MEANS ON SAID ROCKER ARM OUTER END CONNECTED TO SAID TOGGLE KNEE JOINT TO PIVOT SAID KNEE JOINT TO COCK SAID LINKS TO RAISE SAID ROCKER ARM AND TO STRAIGHTEN AND LINKS TO LOWER SAID ROCKER ARM, AT LEAST ONE JAW HAVING A BOTTOM END PIVOTALLY CONNECTED TO SAID ROCKER ARM FOR RAISING AND LOWERING THEREWITH; SAID JAW HAVING AN UPPER END INCLUDING A HEMMING STEEL POSITIONED RELATIVE TO SAID ANVIL; AND FOLD POWER MEANS ON SAID TOP PIN PIVOTALLY CONNECTED TO SAID JAW UPPER END FOR MOVING SAID HEMMING STEEL IN A SIDE DIRECTION RELATIVE TO SAID ANVIL; SAID FOLD POWER MEANS UPON ACTIVATION MOVING SAID JAW AND HEMMING STEEL IN A SIDE DIRECTION TO FOLD A FLANGE OVER ON A WORKPIECE ON SAID ANVIL; SAID CLINCH POWER MEANS UPON ACTIVATION MOVING SAID LINKS, JAW, AND HEMMING STEEL IN A DOWN DIRECTION TO CLINCH A FLANGE DOWN ON A WORKPIECE ON SAID ANVIL IN AN IRONED-OUT HEM. 